1. Field of the Invention
The present invention relates to a semiconductor device provided with a temperature sensing diode for detecting a temperature of a semiconductor substrate and a manufacturing method thereof.
2. Background Art
In power modules such as IPM (intelligent power modules), a temperature sensing diode made of polysilicon or amorphous silicon is incorporated in an IGBT (insulated gate bipolar transistor) thereof. By monitoring VF characteristics of this temperature sensing diode, an operating temperature thereof is managed and protected.
Conventionally, a thick oxide film is formed on a substrate, polysilicon is formed thereon, and ions are injected, and in this way, a temperature sensing diode having a p+-type layer/n−-type layer/n+-type layer is formed. Therefore, the temperature sensing diode is formed on the thick oxide film and located away from an emitter region which is a heat generating source from the standpoint of layout, resulting in poor sensitivity to temperature inside the semiconductor. On the other hand, a temperature sensing diode is proposed in which p-type and n-type polysilicon are formed in a trench (e.g., see Japanese Patent Laid-Open No. 2013-033970).